JPH0443928A - Measuring method for emissivity and temperature of object to be measured - Google Patents

Abstract

PURPOSE:To accurately find the temperature of the object to be measured by varying the measurement distance of the pocket and finding variation in the output of a heat radiation detector, and finding the emissivity of the object from the output variation value and data on an object whose emissivity is already known. CONSTITUTION:Both radiation detection heads 13a and 13b are arranged at the same distance from the object 16 to be measured and the output of each heat radiation detector 12 corresponding to the same measurement distance h1 is inputted to a storage arithmetic unit 14. When the outputs are both supplied, the storage arithmetic unit 14 calculates the emissivity epsilons of the object 16. Then the obtained emissivity epsilons is used to find the output E(T) of the heat radiation detector 12 at the time of a black body from, for example, E(epsilons,C1)/epsilons, thereby easily finding the temperature T of the object body. The temperature T of the object body is displayed on a display device 15. Thus, the emissivity of the object body is also found, so the temperature of the object body can accurately be found without any temperature measurement error due to a difference in emissivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of measuring the emissivity and temperature of an object to be measured.

[Conventional technology]

As is well known, in the radiation thermometry method, which measures the temperature of an object using heat radiation from its surface, if the object to be measured is not a black body, how can the unknown emissivity of the object be determined? The issue is how to process the temperature and reduce temperature measurement errors caused by emissivity. Therefore, as a radiation thermometer devised to reduce temperature measurement errors due to emissivity, there is a known radiation thermometer as shown in FIG. 8, which is an explanatory diagram of the configuration of its radiation detection head.

That is, in FIG. 8, 51 is a hemispherical cavity (hemispherical cavity) whose inner surface is gold-plated, and a measurement hole provided at the apex of this hemispherical cavity 51 has, for example, a silicon cell. A thermal radiation detector 52 using a detection element such as a thermopile or the like is provided. When the radiation detection head 53 configured in this way is positioned close to the measurement surface of the object to be measured, the measurement surface and the hemispherical cavity 51
Due to multiple reflections of radiation from the measurement surface and the inner surface, the condition approaches a black body condition, and the apparent emissivity is increased. This reduces temperature measurement errors due to emissivity because the object to be measured is not a black body.

[Problem to be solved by the invention]

However, in the above-mentioned radiation thermometer that uses multiple reflections, is it possible to reduce the temperature measurement error due to differences in the emissivity of the measured object, or is it possible to calculate the emissivity of the measured object? Therefore, if the emissivity is small, for example, about 0.5 to 0.6, there is a drawback that large temperature measurement errors are likely to occur due to fluctuations in the measurement distance.

This invention was made in view of the above points, and
It is an object of the present invention to provide a new measuring method that can accurately measure the temperature of an object to be measured without causing a temperature measurement error due to a difference in emissivity by also determining the emissivity of the object to be measured.

[Means to solve the problem]

In order to achieve the above object, the measurement method according to the invention of claim 1 is provided in advance by installing a thermal radiation detector at the position of the measurement hole of the cavity in each of a plurality of objects having different known emissivities and at the same temperature. Measure the output of the thermal radiation detector by changing the measurement distance between the installed radiation detection head and the object, and measure the emissivity of the relationship between the measurement distance and the output of the thermal radiation detector at each known emissivity. When measuring the temperature of the object to be measured, measure the output of the thermal radiation detector by changing the measurement distance between the radiation detection head and the object to at least two different distances, and measure the output of the thermal radiation detector. The present invention is characterized in that the emissivity of the object to be measured is determined from the change in , and the emissivity measurement data, and the temperature of the object to be measured is measured using the determined emissivity.

Further, in the measurement method according to the invention of claim 2, thermal radiation detectors are arranged in advance at the positions of measurement holes of cavities that have mutually different multiple reflection characteristics in each of a plurality of objects having different known emissivities and at the same temperature. Using the two radiation detection heads set up, the output of each thermal radiation detector is measured by changing the measurement distance between each radiation detection head and the object. The relationship between the measurement distance and the output of the thermal radiation detector is obtained as emissivity measurement data, and when measuring the temperature of the object to be measured, the measurement distance between both radiation detection heads and the object to be measured is the same, and each temperature is The output of the radiation detector is measured, the emissivity of the object to be measured is determined from the change in this output and the data for emissivity measurement, and the temperature of the object to be measured is measured using the determined emissivity. It is characterized by

[For production]

The measurement principle according to the invention of claim 1 will be explained with reference to FIG. Figure 2 shows the relationship between the radiation detection head and the object using a radiation detection head with a thermal radiation detector placed at the measurement hole position of the cavity for each of a plurality of objects whose emissivity, expressed as 81 to ε, is known. FIG. 7 is a diagram showing the relationship between the measured distance and the output of the thermal radiation detector when the measured distance is changed. This figure shows that the output of the thermal radiation detector decreases as the radiation detection head moves away from the surface of the object to be measured, and that changes in the output of the thermal radiation detector due to changes in measurement distance tend to vary depending on the emissivity. From this, it is possible to conversely find out the emissivity from the change in the output of the thermal radiation detector due to the change in the measurement distance. Therefore, data for emissivity measurement as shown in Fig. 2 is obtained in advance, and the change in the output of the thermal radiation detector due to the change in the measurement distance on the object to be measured is determined, and the value of this output change and the emissivity measurement are calculated. The emissivity of the object to be measured can be determined using the value of the output change corresponding to the change in the measurement distance when measuring the temperature of the object to be measured for an object with a known emissivity obtained from the data. Furthermore, the temperature of the object to be measured can be measured using this emissivity.

The measurement principle according to the invention of claim 2 will be explained with reference to FIG. FIG. 6 shows that for each of a plurality of objects whose emissivities, represented by ε1 to ε4, are known, two radiation detection heads with thermal radiation detectors placed at the measurement holes of cavities with different multiple reflection characteristics are used. FIG. 7 is a diagram showing the relationship between the measured distance and the output of each thermal radiation detector when the measured distance between each radiation detection head and an object is changed. The figure shows that the output of each thermal radiation detector differs even if the emissivity is the same depending on the multiple reflection characteristics of the cavity, and the change in the output of each thermal radiation detector due to differences in cavities tends to differ depending on the emissivity. It shows. From this, it is possible to conversely find out the emissivity from the change in the output of each thermal radiation detector when cavities with different multiple reflection characteristics are used. Therefore, emissivity measurement data as shown in Figure 6 at a known emissivity is obtained in advance, and the output of each thermal radiation detector due to the difference in the cavity of the object to be measured when the measurement distance is the same is determined in advance. Using this output change value and the output change value of each thermal radiation detector at the measurement distance when measuring the temperature of an object with a known emissivity obtained from the emissivity measurement data, It is possible to determine the emissivity of the object to be measured. Furthermore, the temperature of the object to be measured can be measured using this emissivity.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 is a configuration explanatory diagram showing an example of a radiation temperature measuring device for carrying out the method according to the invention of claim 1, FIG. 2 is an explanatory diagram of emissivity measurement data according to the invention of claim 1, and FIG. The figure is a diagram for explaining an example of the procedure for determining the emissivity of a measured object according to the invention of claim 1, and FIG. 4 is another example of a radiation temperature measuring device for carrying out the method according to the invention of claim I. FIG.

In Figure 1, ■ is a hemispherical cavity whose inner surface is gold-plated and has a high reflectance mirror surface, and 2 is a hemispherical cavity 1.
This is a thermal radiation detector disposed at the position of the measurement hole provided at the apex of. This hemispherical cavity 1 and the thermal radiation detector 2 constitute a radiation detection head 3. 4 is a storage/arithmetic device, 5 is a display device, and 6 is an object to be measured having an unknown emissivity εS and whose temperature is to be determined.

Regarding the measurement of the emissivity and temperature of the object to be measured 6 using the radiation temperature measuring device configured as described above, FIGS.
This will be explained below without reference to FIG.

First, without referring to FIG. 2, the emissivity measurement data stored in advance in the storage/arithmetic device 4 will be explained. For each of a plurality of objects having different known emissivities and under the same temperature condition, the measurement distance between the radiation detection head 3 and the object is changed, and the measurement distance and thermal radiation for the plurality of objects that have a known emissivity are changed. The relationship with the output E of the detector 2 is measured, and this is stored (input) in advance in the storage/arithmetic unit 4 as emissivity measurement data.

In the illustrated example, data for emissivity measurement is obtained from five types of objects having known emissivities and ~ε (larger subscript numbers represent larger emissivities). As shown in the figure, the output E of the thermal radiation detector 2 shows a tendency to decrease as the measurement distance increases, or that the degree of change varies depending on the emissivity.

Data for emissivity measurement having such characteristics is stored in advance in the storage/arithmetic device 4, and the temperature of the object to be measured 6 is measured. First, the measurement distance between the radiation detection head 3 and the object to be measured 6 is determined by the distance h
1, and the output E (εS, hl) of the thermal radiation detector 2 at the measurement distance h1 is input into the storage calculation bag f14.

Subsequently, the radiation detection head 3 is moved upward, and the measurement distance h
The output E·(εs, ht) of the thermal radiation detector 2 at the time of 2 is input to the storage/arithmetic unit 4. When the above re-output is given, the storage/arithmetic unit 5 first calculates the emissivity and S in the following steps.
is calculated by calculation. That is, the ratio V(εs, has) of the output E(εs, h2) when the measurement distance is h2 to the output E(εs, t++) when the measurement distance is h1 is determined. Next, from the pre-stored emissivity measurement data shown in FIG. 2, the output E (ff
The ratio V(ε+) of the output E(ε, , h,) of the thermal radiation detector 2 to
, To*). Similarly, from the above emissivity measurement data, other known emissivity ε, (n=2 to 5)
In each case, the ratio V( ε,
, h+2).

As a result, the measurement distances hl and h as shown in FIG.
The output ratio V(ε, , has ) of the thermal radiation detector 2 at the known emissivity ε when changed to 2 is obtained. Then, the above output ratio V(εs
, t++*) and the known emissivity ε, (n=1 to 5)
Compare the magnitude relationship of the values with the output ratio v (ε., hat ), and if the relationship is as shown in FIG. I can do what I want.

es= (Cεs−ε4)/(V (ε*, t++
2)-V(ε4.has))l'(V(εs
, hat)■(ε, , hat))+ε4 Then, using the obtained emissivity εS, for example, E(εs,
h, )/εS to the output E of the thermal radiation detector 2 at the blackbody
By determining (T), the temperature T of the object to be measured can be easily determined. Note that the temperature T of the object to be measured is displayed on the display device 5.

In this way, the emissivity of the object to be measured can also be determined, so the temperature of the object to be measured can be accurately determined without causing temperature measurement errors due to differences in emissivity. In the above embodiment, - number of radiation detection heads 3 are used to measure the temperature of the object to be measured 6, but as shown in FIG. Other radiation detection heads 3 may be positioned at different measurement distances. Alternatively, three or more measurement distances may be used, and an interpolation operation may be performed using the output of the thermal radiation detector at this time to determine a change in the output of the thermal radiation detector due to a change in the measurement distance of the object to be measured.

FIG. 5 is a configuration explanatory diagram showing an example of a radiation temperature measuring device for carrying out the method according to the invention of claim 2, FIG. 6 is an explanatory diagram of emissivity measurement data according to the invention of claim 2, and FIG. The figure is a diagram for explaining an example of the procedure for determining the emissivity of the object to be measured according to the second aspect of the invention.

In FIG. 5, reference numeral 13a denotes a first radiation detection head, in which a thermal radiation detector is installed at the position of a measurement hole provided at the apex of a hemispherical cavity lla whose inner surface is gold-plated and has a highly reflective mirror surface. 12 are arranged. Also,
Reference numeral 13b denotes a second radiation detection head, in which a thermal radiation detector 12 is disposed at the position of the measurement hole at the apex of a hemispherical cavity llb having a smaller diameter than the hemispherical cavity lla of the first radiation detection head 13a. It is composed of 14
is a storage/arithmetic device, 15 is a display device, and 16 is its emissivity ε
This is the object to be measured for which S and temperature are to be determined.

Measurement of the emissivity and temperature of the object to be measured 16 using the radiation temperature measuring device configured as described above will be described below with reference to FIGS. 5 to 7.

First, with reference to FIG. 6, the emissivity measurement data stored in advance in the storage/arithmetic device 14 will be explained. The two radiation detection heads 13a and 13b are provided with cavities having different multiple reflection characteristics for each object having a known emissivity and under the same temperature condition.
is used to measure the relationship between the measurement distance and the output of each thermal radiation detector 12 when the measurement distance between each radiation detection head 13a, 13b and the object is changed, and this is used as emissivity measurement data. The data is input in advance to the storage/arithmetic unit 14 as follows.

In the illustrated example, emissivity measurement data is obtained from four types of objects having known emissivities ε, ~ε, (the larger the subscript number, the higher the emissivity). As shown in the figure, if the multiple reflection characteristics of the cavities 1la and llb are different, the output of the thermal radiation detector 12 will be different even if the emissivity is the same, and the change in the output of the thermal radiation detector I2 due to the difference in the cavities 1la and llb is Each shows different trends depending on the emissivity. In addition, in FIG. 6, the characteristic showing the relationship between the measurement distance and the output of the thermal radiation detector is shown as a straight line, but in reality it is a curve sloping to the lower right (see FIG. 2).

Data for emissivity measurement having such characteristics is stored in advance in the storage/arithmetic device 14, and the temperature of the object to be measured 16 is measured.

First, both radiation detection heads 13a and 13b are connected to the object to be measured 1.
6 and the outputs of the respective thermal radiation detectors 12 at the same measurement distance h1 are input to the storage/arithmetic device 14. When both of the above outputs are given, the storage/arithmetic unit 14 calculates the emissivity εS of the object to be measured 16 in the following procedure. That is, the output E(εS) of the thermal radiation detector 12 of the first radiation detection head 13a.

Ratio of the output E (εs, Cz) of the thermal radiation detector 12 of the second radiation detection head 13b to C+) V Ce s,
Find Cat). Next, from the emissivity measurement data shown in FIG. 6 that has been inputted in advance, if the emissivity is 81 and the measurement distance is h1, the output E (C1, C+ ) of the thermal radiation detector 12 of the second radiation detection head 13b E Cat
, C2) (7) Find the ratio v(ε+, c+*).

Similarly, from the above emissivity measurement data, it is determined that the thermal radiation detector 12 of the first radiation detection head 13a has a different known emissivity ε, (n=2 to 4) at each measurement distance.
The second radiation detection head 1 for the output E(ε, ,C,) of
The ratio V of the output E (ε, , C2) of the thermal radiation detector 12 of 3b
(Determine ε., C,, >.

Thereby, as shown in FIG. 7, the output ratio V of each thermal radiation detector I2 at a known emissivity ε at a measurement distance h1
(C1, C1□) is obtained. Then, the above output ratio V (εs + C + □) obtained from the object to be measured 16 and the above output ratio V (εs,
C+z), and if the relationship is as shown in FIG. 7, for example, then the emissivity εS of the object to be measured 16 can be determined using the following equation.

εS= ((ε, -ε,)/(V (ε* + C
at )−V(εi+Cat))l ”(V
(εs, Cl2) ■ (ε, , C,,') ) ten ε.

Then, using the obtained emissivity εS, for example, E(εs,
Output E of thermal radiation detector 12 at black body from Cυ/εS
By determining (T), the temperature T of the object to be measured can be easily determined. Note that the temperature T of the object to be measured is displayed on the display device t15. In this way, the emissivity of the object to be measured can also be determined, so the temperature of the object to be measured can be accurately determined without causing temperature measurement errors due to differences in emissivity.

[Effects of the Invention] As explained above, according to the measurement method according to the invention of claim 1, the measurement distance at the object to be measured is changed to determine the change in the output of the thermal radiation detector, and the value of this output change is calculated. This method calculates the emissivity of the object to be measured from the emissivity measurement data of an object with a known emissivity obtained in advance, and measures the temperature of the object. The temperature of the object to be measured can be determined accurately without causing any errors.

Further, according to the measurement method according to the invention of claim 2, when the same measurement distance is obtained using two radiation detection heads each having a thermal radiation detector arranged at the position of the measurement hole of the cow Yachti which has different multiple reflection characteristics, The change in the output of each thermal radiation detector due to the difference in the cavity in the measured object is determined, and the radiation of the measured object is determined from this output change value and the emissivity measurement data for the object with a known emissivity. Since this method calculates the emissivity and then measures the temperature, it is possible to accurately determine the temperature of the object to be measured without causing temperature measurement errors due to differences in emissivity.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing an example of a radiation temperature measuring device for carrying out the method according to the invention of claim 1, FIG. 2 is an explanatory diagram of emissivity measurement data according to the invention of claim 1, and FIG. The figure is a diagram for explaining an example of the procedure for determining the emissivity of a measured object according to the invention of claim 1, and FIG. 4 is another example of a radiation temperature measuring device for carrying out the method according to the invention of claim 1. FIG. 5 is a configuration explanatory diagram showing an example of a radiation temperature measuring device for carrying out the method according to the invention of claim 2, and FIG. 6 is an explanatory diagram of emissivity measurement data according to the invention of claim 2. FIG. 7 is a diagram for explaining an example of the procedure for determining the emissivity of a measured object according to the invention of claim 2, and FIG. 8 is a diagram for explaining the configuration of a radiation detection head of a conventional radiation thermometer. be. L 1la 111b - hemispherical cavity, 2.12 - thermal radiation detector, 3 - radiation detection head, 13a - first radiation detection head, 1
3b-Second radiation detection head, 4.14-Storage/arithmetic device, 5.15-Display device, 6.1
6 Object to be measured. Patent applicant Kobe Steel, Ltd.

Claims (2)

[Claims] (1) In advance, for each of a plurality of objects having different known emissivities and at the same temperature, change the measurement distance between the object and the radiation detection head, which has a thermal radiation detector installed at the position of the measurement hole of the cavity. The output of the thermal radiation detector is measured using The output of the thermal radiation detector is measured by changing the measurement distance between the radiation detection head and the object to be measured to at least two different distances, and the radiation of the object to be measured is determined based on the change in output and the emissivity measurement data. A method for measuring the emissivity and temperature of an object to be measured, characterized in that the temperature of the object to be measured is measured using the determined emissivity. (2) Using two radiation detection heads with thermal radiation detectors placed at the measurement holes of cavities with different multiple reflection characteristics for each of multiple objects with different known emissivities and at the same temperature. Then, the output of each thermal radiation detector is measured by changing the measurement distance between each radiation detection head and the object, and the measurement distance and the output of the thermal radiation detector at each of the known emissivities are measured in both radiation detection heads. The relationship between the two radiation detection heads and the object to be measured is determined as data for emissivity measurement, and when measuring the temperature of the object to be measured, the output of each thermal radiation detector is measured with the measurement distance between the two radiation detection heads and the object to be measured to be the same, The emissivity of the measured object is determined from the change in output and the emissivity measurement data, and the temperature of the measured object is measured using the determined emissivity. How to measure emissivity and temperature.